A sleeping white dwarf exploded in 2009, after millions of years of being quiet. Polish researchers studied the trails left by the event.
The white dwarf is named V1213 Cen, and they are located in the Scutum-Centaurus part of the Milky Way. The binary star is composed by a dim red dwarf and a white dwarf which had been dead for many years.
The system involves a parasitic connection, as the dead star consumes the red dwarf and occasionally bursts into the flares.
The Warsaw Research
The study supports with data a theoretical model that was already designed by scientists.
In the end, the white dwarf would accumulate enough quantities of hydrogen and helium to reach internal temperatures and pressures that ultimately climaxed in a reaction of thermonuclear fusion.
At that moment, matter and energy are released in an explosion, filling the sky with light, just like a classical nova.
The explosion of V1213 Cen happened in 2009 when the telescopes caught a glance of the event.
The classical novae are difficult to study because they are transient. However, the 2009 explosion offered scientists the opportunity to observe the explosion and the aftermath. The Optical Gravitational Lensing Experiment collected data before and the explosion, supporting scientists in their pursuits.
The Optical Gravitational Lensing Experiment is based at the University of Warsaw and had been collecting data on the Universe since 1992.
The White Dwarf Cycle of Explosions
The study findings match an already known theoretical model that bears the name “hibernation hypothesis.” However, the scientists still did not find out when a white dwarf would turn into a nova.
The researchers created a graphic with all the light variations coming from the binary star. Based on the quantity of light, the scientists managed to obtain information on the amount of mass that was transferred between the two stars.
The researchers explain that the light curve is disturbed by any quantity of matter that reaches the star’s surface. The outburst happens when the mass-transfer rate becomes unstable.
The monitoring of V1213 Cen marked the evolution of the mass-transfer rate over the years, before and after the nova eruption. The authors hope that the data coming from their observation would sustain future research and may unveil the secret of what makes a white dwarf explode.
The hibernation hypothesis involves the fact that after a supernova explosion, the mass-transfer rate increases and then starts to decrease over a period of million years. The transfer of matter fades away, and the star enters a hibernation phase.
The process does not stop here, as the white dwarf accumulates matter again and increases its internal pressure and temperature up to the point when it explodes again.
Image Source: Wikipedia